The basic idea is that you can continuously document what your system should do (high level and detailed features), how it should prove it has done that, option

The basic idea is that you can continuously document what your system should do (high level and detailed features), how it should prove it has done that, optionally how you want it to do it (architecture and code style etc). The multi-model AI part is just the (current) tool to help avoid bias and make fine tuned selections for certain parts of the task. Eventually large complex systems will be built and re-built from a set of requirements and software will finally match the stated requirements. The only "legacy code" will be legacy requirements specifications. Fix your requirements, not the generated code.